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Ex 4.5, 18 - If A is an invertible matrix of order 2, det(A-1) - Ex 4.5

  1. Class 12
  2. Important Question for exams Class 12
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Ex 4.5, 18 If A is an invertible matrix of order 2, then det(A−1) is equal to A. det (A) B. 1﷮det (A)﷯ C. 1 D. 0 We know that AA-1 = I Taking determinant both sides AA−1﷯= |I| |A| |A-1| = |I| |A| |A-1| = 1 |A-1| = 1﷮|A|﷯ Since |A| ≠ 0 Hence, |A-1| = 1﷮|A|﷯ is valid Thus, the correct answer is B

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